The Chaos Theory
by cooldood101
Summary: "Chaos: When the present determines the future, but the approximate present does not approximately determine the future." One slight, insignificant, logical change in a particular battle during the Third Shinobi World War results in cataclysmic changes. The ninja world will never be the same.
1. Prologue

Prologue

It all started with a single thought. If he was going to save Rin he would destroy anything and anyone is his path. So when he and Kakashi engaged the Iwa nin, Kakko, he knew the outcome would be the bastard's death. He felt a sense of euphoria fighting with Kakashi. Slash, parry and dodge. It wasn't just the Sharingan, he idly noted as he leaned back to dodge a decapitating slash. Fighting with Kakashi was more natural than ever. They instinctively knew where the other would be, and they moved together in synchronization, faster than Obito had ever been capable of. Then Obito maneuvered the enemy into a position where he was off balance and Kakashi slashed his chest.

Warm, hot blood spurted on to his face. The ninja fell to the ground and Kakashi seamlessly transition from fighting in a death match to running towards where Rin was bound. Obito would have followed, had he not- with his new visually acuity- noticed their enemy twitch. He kneeled down a kunai still firmly in his grip. He stared at his opponent's face. He could see both fear and shock on his opponents face. Had he not been an Iwa shinobi with a heart of stone he might have cried. But Obito wasn't moved. He realised now what his nindo was. When it came to protecting Rin, he wasn't capable of mustering even a shred of compassion. He buried a kunai in the man's throat. Blood covered his hand. He used his sleeve to wipe his face, and then wiped his hand on the corpse's torso.

"Kakashi" gasped Rin. Obito looked up from the corpse. Kakashi must have released the genjutsu, as her chakra no longer looked distorted to him. "Obito." He stared at her, her warm brown eyes engulfing him. He felt like a fist was going to break through his chest. The relief was that palpable. Rin was okay.

"Rin, Kakashi, let's get out of here" he spoke, trying to ignore the lump in his throat.

They sprinted for the exit, Kakashi taking point. Obito spared a glance for his fallen enemy, but felt nothing but triumph at the sight. That feeling was short-lived however; when they reached the exit they were surrounded. A dozen Iwa shinobi, chunin level at least, with matching smirks, bulk and, of course, murderous intent. Obito felt his heart almost stop. This was followed immediately by a helpless anger at their situation

"Kakashi, what should we do?" asked Rin, a kunai in her hand. Kakashi glanced at her sideways.

"Obito, take Rin and get out of here. I'll buy us some time" said Kakashi calmly, his sabre in one hand, and Minato-sensei's kunai in the other.

"Like hell," snarled Obito. "I'm not going to leave you behind".

"We came here to save Rin. Don't argue. Get out of here and run. I'm the team leader. We've failed the mission. The least I can do is protect my friends".

Obito was shocked. Kakashi had never before referred to anyone as a friend. Not in his presence at least. And here he was, about to die for them. He felt something is his chest wrench. Then the world became vividly clear.

"Alright, Kakashi-taichou". Kakashi's relief was almost palpable. Until he finished the sentence that is. "You can have me court-martialled for disobeying you when we all get back home".

Kakashi sighed, and turned back to Rin, resigned. "You're our team's only medical ninja. Stay back near the entrance of the cave while we take care of this". She didn't look convinced, but nodded and stepped back.

And then it began. Doton jutsu were hurled at them, but they were prepared. Lightning sparked from Kakashi's hand and destroyed earth dragons and spears. Obito's katon jutsu were just as effective in tearing up the landscape. Everything seemed to be moving in slow motion. And when a ninja behind Kakashi weaved signs for a jutsu to kill him, Obito weaved them faster, using an earth wall to protect him, and then a dragon to crush Kakashi's would be killer. Their ninjutsu battle was a stalemate and the fury of the Iwa nin at losing one of their friends lead to them engaging in close combat.

It was nothing like their battle before in the cave. They fought back to back, surrounded by their enemies. As fast and skilled as Kakashi was there was no comparison between them. Obito knew his Sharingan had just evolved again, probably to the highest level. He could see everything. He slashed, parried, blocked and dodged against three ninja at a time. He was making small nicks and wounds on each of them, but was untouched himself. He substituted with a rock clone of himself – and mentally thanked his ancestors for the jutsu copying capabilities of the Sharingan- and roasted one of them with a fireball.

Kakashi on the other hand was a jounin. He knew they most likely wouldn't survive. Obito was doing well, and he was faring well also. However, these ninja weren't stupid. When Obito killed another of their ranks they jumped back and regrouped.

"Let's take it nice and slow everyone," one of them ordered. "These Konoha dogs are better than we thought. Hem them in and we'll finish them off". Divide and conquer. It was a very basic tactic, but Kakashi knew that it would be enough to spell their doom.

"Obito," roared Kakashi. "Back me up!"

But it was not to be. Three of their enemies intercepted and engaged him. Three more lunged towards Kakashi. The rest started forming hand seals. Kakashi didn't have the Sharingan, but he could predict what was going to happen. Obito had overestimated himself, underestimated their opponents, and was going to die. Obito kicked one of the ninja away. The other two tried to flank him, but he jumped back and flung his kunai at them whilst still in mid-air. One buried itself in the first one's eye; the second was imbedded in the other's flak jacket. Unlike his friend he might have survived. Then everything happened at once.

There was no chance to shout out a warning. He was floating. He was helpless. A ninja came up from the ground behind Obito, a ninjato held in both hands to impale Obito. Kakashi flung his sensei's kunai at his head, but regardless it would be too late. There was a whistle of sound, a slight shift in the air. The blade pierced through flesh. It may as well have been butter. A heartbeat later the kunai impaled the Iwa nin in his temple. He collapsed, dead. But it was too late.

Obito had landed on his feet. Kakashi's eye widened, his mask hardly hiding his expression. Obito's Sharingan burned the image into his mind. He would never forget it, as long as he lived. He turned around with dread, and couldn't comprehend what he saw. It took an instant for the sight to register. Then he let out a primal scream of rage.

The remaining Iwa ninja rushed him and Kakashi. They were undeterred, both by the death of their comrades or one of their enemies. Or even the sudden feeling of dread they all felt. They ignored the heaviness in the air with the practice of experienced warriors. They were true shinobi. But in the space of about a minute, they would be nothing at all.

The first one to reach Obito was probably the luckiest one. For him, it was all over before he could understand what had happened. He struck at Obito with a katana. It passed through him. For a second he gaped at him. Then he was crushed into a pulp on the ground. The entire battlefield, save Obito froze; the Iwa nin looked at each other, at Kakashi and at their friend, crushed into a paste at Obito's feet. It was clear on their faces that they unanimously felt that the ignominy and humiliation of a ninja's death wasn't worth it. Not at the hands of children. Too bad they never had a choice in the matter.

The remaining enemies turned and bolted towards the forest. But they would never make it. Obito, cloaked in a skeletal orange golem was in their midst before they knew it. Some tried to attack. The smarter ones knew their demise was inevitable. They squeezed their eyes shut. It was over in a few moments, but he continued to pound at their mutilated bodies with his bare hands, long after his gargantuan guardian had dissipated. He would have stayed there forever. But he was quickly jerked back to reality.

"Obito," whispered Rin. "Stop. Please."

It was like his head had been dunked in cold water, and he was at her side in an instant. Kakashi was at her side, futilely pressing a cloth around the short sword that was hilt deep in her chest. He lifted her up cradled her to his chest. He pleaded with Kakashi, begged him to save her. He was a jounin; he had to know some medical ninjutsu. But it was quite obvious from the anguish on Kakashi's face that there was nothing he could do. He was pressing his left hand with the cloth firmly on Rin's chest. The other hand was clenched in a fist. He had never felt more useless in his life. Everything had gone to hell.

"Obito, it's okay." She paused, and coughed up some blood. "I'm glad I got to die saving you"

No. He couldn't allow this to happen. There were tears streaming down his face. And then he was rambling, a stream of jumbled words and sentences. How he loved her. How he was meant to save her. How she wasn't supposed to die. How he would die if she did. He vowed to die if she did. She couldn't die. The world couldn't exist without her.

Her eyes had been closing, she had been losing consciousness. But they widened at his last declaration and, with unprecedented strength she reached up and grabbed his hand. How dare he, she told him firmly, disrespect and dishonor her like that. If he died, her sacrifice was for nothing.

"I'm glad to die," she gasped with her last breath. "If it means you become Hokage.


	2. Chapter 1

One moment he wasn't there. The next he was. The voice appeared before he did.

"So, Hokage-sama," he drawled. "Who do you want me to kill?"

The Anbu flinging themselves from the shadows may as well have strolled over, for all the good it would have done. The robed man in his chair, looking out his window, didn't react to the foreign presence behind him. He merely waved a hand from behind the back of his chair to his ANBU to stand down. One of them still had a ninjato drawn when he swiveled around. He raised an amused eyebrow to the sight, and stood up.

"Leave us," he ordered. The bodies started to melt into the shadows before he corrected himself.

"Not you, Kakashi. I'd like you to join us. And take off your mask too."

Kakashi pulled off the mask, which vaguely resembled the form of some canine and hung it on his belt, before stepping forward alongside the newcomer. The Hokage walked around his desk and leaned back against it, his arms folded. Although the three men were of similar stature, as they faced each other one seemed larger than the other two.

The Hokage took off his hat and placed it on his desk behind him. A shock of blond hair framed his face. He clucked his tongue mockingly at the hooded newcomer. "It's not always about killing people you know. Oh, and if Kakashi has to take off his mask…."

The newcomer scoffed for a moment, then pulled back his hood and a plain mask off his face. His eyes were as black as his close cropped hair. It was his turn to raise an eyebrow at his boss.

"I'm serious," shrugged Minato, trying to fight a smile. "This time it's about giving life".

The brunette smiled, while Kakashi grimaced- his attempt at a smile. "Congratulations sir," he said stiffly. "But with all due respect, what has this got to do with us?"

"I'm glad you asked Kakashi," smiled Minato. "You're fired."

No one reacted for a second. Kakashi was stunned, but too disciplined to exclaim. His companion on the other hand had no such qualms and began to guffaw. "Holy crap, Kakashi," he started. "Are you that shitty an ANBU that your own sensei had to fire you?" he asked, still chuckling. Kakashi glared at him viciously, but they both quieted when Minato sighed halfheartedly at their antics.

"It's quite the contrary, actually. You're talents are being wasted in the black ops. I think it's time I took a keener interest in both your developments." He started pacing for a moment, before walking back around to sit in his leather chair, resting his elbows on the desk with his fingers interlocked. "For example, there's something I'd like you to attend with me. It'll give you a chance to observe fuinjutsu at the highest level. An area both of you could improve. Especially you, Obito" he finished sternly. Obito rubbed the back of his head sheepishly.

Kakashi looked like he wanted to protest, but Minato cut across him.

"Think of it as a temporary reassignment. I want to rotate you a little through some different division. Broaden your horizons. And you'll have Obito alongside you. It's been quite a while since you two have teamed up."

For some reason, neither of them looked mollified by that statement.

"You're not looking for a successor, are you sensei?" asked Obito slyly.

"I'm sure Sensei's reign will be just as long as Hiruzen-sama's," scowled Kakashi.

Minato merely chuckled, but suddenly his laughter faltered and his expression settled on grim. "Perhaps I'm not looking for the fifth Hokage. But I need you two to be leaders. You're already fine soldiers. It's about time you transcend that. There may come a time when the village needs warriors, who are not just willing, but able to step up to the mantle of Hokage, or any other mantle."

Obito frowned for a moment, a brief glimpse of honest sobriety. Then he chuckled. "Are you sure that's wise Sensei? Kakashi I can understand, but me? I'm just a regular Uchiha…." He trailed off. His tone was light, but there was an unmistakable darkness in his words. Kakashi glanced sideways at him, surprised and suspicious. Whether Obito was being sarcastic, or implying something deeper, he didn't know.

"Isn't this what you wanted Obito?" asked Minato, his voice sounding like a razor. And then there was tension in the room. The long tendon of his index finger was prominent, his hands not moving an inch from the desk.

"Well Sensei, sometimes when my sort get what we want, it throws us off a little" he smirked, but there was something dark in his expression. "I only wonder if the council will be more surprised than I was.

Minato didn't respond to that.

"By your leave Hokage-sama?"

"You may go Obito. Officially, you two are going to double as my personal assistants and bodyguards. Kakashi, I'll need you to submit to me a shortlist of replacement for your squad. Delta squad, was it? He didn't wait for an answer. "He nodded to Obito. I'll update you within the next few days. Until then, I'd make the most of my time relaxing if I were you."

Obito nodded, and then disappeared. The air felt like it was being sucked out of the room.

"Kakashi, do me a favour and open the window," asked Minato. Kakashi complied, and before he could move: "…and close it. Then come sit down".

"What's going on?" asked Kakashi.

"You've become too used to ANBU Kakashi." It wasn't just a statement, it was a criticism. Kakashi winced.

"The problem with ANBU missions is that there's no ambiguity in your orders or your enemies. But that's not how the world always works Kakashi."

"I'm not a fool," said Kakashi quietly. "I know something is going on. Are we going to war?"

Minato smiled. "Perhaps. But our enemies are not always outside Konoha's walls."

"Is that why someone was spying on us a moment ago?"

"There's always someone watching me"

"Watching? Not spying?"

"You're learning Kakashi. But I need you to learn quicker. Obito already eclipses you."

Kakashi stared at him with incredulity. "What? I don't even know how to respond to that…"

"You are truly a genius Kakashi. You have an intuitive grasp of the shinobi arts, and a singular potential which reminds me of the Professor. And you have a mind sharper than a blade."

Kakashi might have almost blushed underneath his mask. That was high praise indeed.

Minato's gaze hardened. "Yes, you could be my successor in a decade or two. But you're not where _I_ need you to be right now."

"So what do I do?" whispered Kakashi, his gaze on Minato's face only by sheer force of will.

"You may be able to see and do what Obito cannot. But unlike you, Obito is a schemer."

"You need to be one too."


End file.
